Duplicate along path with uniform spacing
There are generally three possibilities to cause such problem in this particular case:


The resolution of the curve path, which is the least possible factor here;
It seems that you are using Dupliface, it will also be curved by the Curve modifier see Figure 1;
The edge of per panel should better coincide with the joint, in order to minimize the disjoint look. See Figure 2.





I think the most accurate way is to use rigid body constraints, but that would be way too complicated comparing to this way. Hope it helps.